Field of the Invention
The present invention relates to temperature control in a networking device such as a network switch.
Background of the Related Art
Networking devices like switches used in various types of networks, such as Fibre Channel, Infiniband and Ethernet, do not have the ability to perform thermal throttling. Switches also dissipate about 80-90% of their total power rating once the ports are online, depending on the application, irrespective of whether the ports are being used or not. Unlike central processing units (CPUs) and memory, these networking devices do not have a built-in throttling capability to operate at lower frequency or power state with an acceptable performance impact.
In fan failure modes, higher ambient temperatures and higher elevations, networking devices tend to run at higher operating temperatures. In some instances, these higher operating temperatures can lead to higher leakage current resulting in thermal runaway. When a typical networking device in a datacenter rack or multi-node chassis has insufficient cooling and exceeds a temperature limit, the networking device is designed to shut down. High temperatures may also result in component damage, a reduction in reliability, high bit error rates (BER) or data loss.
Cooling systems for a switch or input/output (I/O) device are typically designed to meet a known set of cooling requirements. However, once the switch or I/O device has been shipped and installed, the cooling system may be used in a more thermally-challenging operating environment than the switch or I/O device was designed to handle. Sometimes an existing switch or I/O device is used, without modification, in a new chassis under different operating conditions in order to avoid additional development or material costs. Furthermore, there is questionable value in customizing a cooling system for every single operating environment just so that the switch or I/O device will remain fully functional under certain unusually strenuous operating conditions. Still, these networking devices need to remain functional regardless of the operating conditions, such as a fan failure or high temperature ambient conditions, even if performance is negatively impacted.